ADS8665: Programming issues

Andres,

Can you send a scope shot of your timing? Include the time base so that we can confirm the timing. Also, what do you mean by “analog value is not well format”? Do you get analog conversion results that are close to what you would expect or are they completely wrong?

Best regards,

Art

Hello,

 Thank you for the response, something i did wrong because i attached the image...ok, this is the files with timing

Andres,

Can you confirm your SPI Protocol (from Table 8)? I believe you are using “SPI-00-S” (data captured on rising edge, SCLK polarity low at CS falling edge). SPI-00-S is the default power up value. Assuming, this is the case I agree that you are reading “ALARM_H_TH_REG” in the second frame. Is your microcontroller in the proper SPI mode? Below is the decoding for your command and the command sequence.

31	30	29	28		27	26	25	24		23	22	21	20		19	18	17	16		15	14	13	12		11	10	9	8		7	6	5	4		3	2	1	0
1	1	0	0		1	0	0	0		0	0	1	0		0	1	0	0		0	0	0	0		0	0	0	0		0	0	0	0		0	0	0	0
						x	x
11001_xx “Read Hword” (xx = 00)								9 bit address 024H Read “ALARM_H_TH_REG”												0000H

The format for the results that is being read from the “ALARM_H_TH_REG” is given by Figure 84 in the data sheet. Based on this figure you are getting INP_ALRM_HYST[7:0] = 93H, AND NP_ALRM_HIGH_TH[15:0] = 0000H. Does this match what you are expecting? If you re-read this register, do you get different results? Did you write something into the register?

Your waveforms look clear and clean. I don’t see any obvious problems. Can you capture the waveform where you write into the ALARM_H_TH_REG? I would like to see a write ALARM_H_TH_REG, followed by a read ALARM_H_TH_REG.  See below:

Thanks,

Art

Hi and thanks,

     Yes the protocol is the default after reset so it is “SPI-00-S” I expect the default value for the register FFFFh because i did not write nothing to the register. I will try to write something and then read the register as you propose.

BR.